php中getip()什么意思? 在开发中有什么作用？

Hi这个getip在PHP中没有原装的函数或者方法..属于后来自己封装的..在开发中主要用于获取客户端的ip地址的如://获得用户IP
function getIP() {
if (! empty ( $_SERVER [\"HTTP_CLIENT_IP\"] )) {
$cip = $_SERVER [\"HTTP_CLIENT_IP\"];
} else if (! empty ( $_SERVER [\"HTTP_X_FORWARDED_FOR\"] )) {
$cip = $_SERVER [\"HTTP_X_FORWARDED_FOR\"];
} else if (! empty ( $_SERVER [\"REMOTE_ADDR\"] )) {
$cip = $_SERVER [\"REMOTE_ADDR\"];
} else {
$cip = '';
}
preg_match ( \"/[\d\.]{7,15}/\", $cip, $cips );
$cip = isset ( $cips [0] ) ? $cips [0] : 'unknown';
unset ( $cips );
return $cip;
}